//    Copyright (C) Kherty.  All rights reserved.
using System;
using System.Globalization;
using System.Windows;
using System.Windows.Data;

namespace OpenLS.Chart.UI.Internals
{
    sealed class Axis3DInfoFactory: IMultiValueConverter
    {
        /// <summary>
        /// Converts source values to a value for the binding target. The data binding engine calls this method when it propagates the values from source bindings to the binding target.
        /// </summary>
        /// <returns>
        /// A converted value.
        ///                     If the method returns null, the valid null value is used.
        ///                     A return value of <see cref="T:System.Windows.DependencyProperty"/>.<see cref="F:System.Windows.DependencyProperty.UnsetValue"/> indicates that the converter did not produce a value, and that the binding will use the <see cref="P:System.Windows.Data.BindingBase.FallbackValue"/> if it is available, or else will use the default value.
        ///                     A return value of <see cref="T:System.Windows.Data.Binding"/>.<see cref="F:System.Windows.Data.Binding.DoNothing"/> indicates that the binding does not transfer the value or use the <see cref="P:System.Windows.Data.BindingBase.FallbackValue"/> or the default value.
        /// </returns>
        /// <param name="values">The array of values that the source bindings in the <see cref="T:System.Windows.Data.MultiBinding"/> produces. The value <see cref="F:System.Windows.DependencyProperty.UnsetValue"/> indicates that the source binding has no value to provide for conversion.
        ///                 </param><param name="targetType">The type of the binding target property.
        ///                 </param><param name="parameter">The converter parameter to use.
        ///                 </param><param name="culture">The culture to use in the converter.
        ///                 </param>
        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
        {
            var floor = toDouble(values[0]).GetValueOrDefault();
            var min = toDouble(values[3]);
            if (min == null)
                min = floor;
            else
            {
                min = Math.Min(min.Value, floor);
            }
            var max = toDouble(values[4]);
            if (max == null)
                max = floor;
            else
            {
                max = Math.Max(max.Value, floor);
            }
            return new AxisInfo(toDouble(values[1]), toDouble(values[2]), min, max);
        }

        private static double? toDouble(object value)
        {
            if (value == null)
                return null;
            if (value == DependencyProperty.UnsetValue)
                return null;
            return System.Convert.ToDouble(value);
        }


        /// <summary>
        /// Converts a binding target value to the source binding values.
        /// </summary>
        /// <returns>
        /// An array of values that have been converted from the target value back to the source values.
        /// </returns>
        /// <param name="value">The value that the binding target produces.
        ///                 </param><param name="targetTypes">The array of types to convert to. The array length indicates the number and types of values that are suggested for the method to return.
        ///                 </param><param name="parameter">The converter parameter to use.
        ///                 </param><param name="culture">The culture to use in the converter.
        ///                 </param>
        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
        {
            throw new NotSupportedException();
        }
    }
}